Engine coolant heater



FIG. 1 is a front perspective view of the engine coolant heater;

FIG. 2 is a front elevation view;

FIG. 3 is a side elevation view, the opposite side being a mirror image;

FIG. 4 is a rear elevation view;

FIG. 5 is a top view; and,

FIG. 6 is a bottom view. 

The ornamental design for engine coolant heater, as shown and described. 